The largest uncertainty in future projections of sea level change comes from the uncertain response of the Antarctic Ice Sheet to the warming oceans and atmosphere. The ice sheet gains roughly 2000 km³ of ice from precipitation each year and loses a similar amount through solid ice discharge into the surrounding oceans. Numerous studies have shown that the ice sheet is currently out of long-term equilibrium, losing mass at an accelerated rate and increasing sea level rise. Projections of sea level change rely on accurate estimates of the contribution of land ice to the contemporary sea level budget. The longest observational record available to study the mass balance of the Earth's ice sheets comes from satellite altimeters. This record, however, consists of multiple satellite missions with different life spans and inconsistent measurement types (radar and laser) of varying quality. To fully utilize these data, measurements from different missions must be cross-calibrated and integrated into a consistent record of change. Here, we present a novel approach for generating such a record that implies improved topography removal, cross-calibration, and normalization of seasonal amplitudes from different mission. We describe in detail the advanced geophysical corrections applied and the processes needed to derive elevation change estimates. We processed the full archive record of satellite altimetry data, providing a seamless record of elevation change for the Antarctic Ice Sheet that spans the period 1985 to 2020. The data are produced and distributed as part of the NASA MEaSUREs ITS_LIVE (Making Earth System Data Records for Use in Research Environments Inter-mission Time Series of Land Ice Velocity and Elevation) project (Nilsson et al., 2021, DOI: https://doi.org/10.5067/L3LSVDZS15ZV​​​​​​​).

中文翻译：

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南极冰盖的海拔变化：1985年至2020年

未来海平面变化预测的最大不确定性来自南极冰盖对变暖的海洋和大气的不确定反应。冰盖增加了大约 2000 公里³每年降水中的冰，并通过将固体冰排放到周围海洋中而损失相似的数量。大量研究表明，冰盖目前处于长期平衡状态，质量加速流失，海平面上升加剧。海平面变化的预测依赖于对陆地冰对当代海平面预算贡献的准确估计。可用于研究地球冰盖质量平衡的最长观测记录来自卫星高度计。然而，该记录由多个卫星任务组成，这些任务具有不同的寿命和不同质量的不一致测量类型（雷达和激光）。为了充分利用这些数据，必须对来自不同任务的测量结果进行交叉校准并将其整合到一致的变化记录中。这里，我们提出了一种新的方法来生成这样的记录，这意味着改进了地形去除、交叉校准和来自不同任务的季节振幅的标准化。我们详细描述了应用的高级地球物理校正以及推导高程变化估计所需的过程。我们处理了卫星测​​高数据的完整档案记录，为 1985 年至 2020 年期间的南极冰盖提供了海拔变化的无缝记录。这些数据是作为 NASA MEASUREs ITS_LIVE（制作地球系统数据记录）的一部分生成和分发的用于研究环境任务间陆地冰速和海拔时间序列）项目（Nilsson et al., 2021, DOI: https://doi.org/10.5067/L3LSVDZS15ZV​​​​​​​）。